Mr. Obama's appeal for Russian forbearance, on an issue that is of critical concern to Moscow, played out at the nuclear security summit in Seoul today. In a speech, Obama said he would ask Mr. Putin to move beyond the dramatic one-third cuts to US and Russian strategic nuclear arsenals agreed to just two years ago in the new START treaty and perhaps even dial the numbers back to levels not seen since the 1950s.

But on the vexing issue of missile defense, which has led the Russians to threaten a possible walkout from the START accord, microphones in the conference room picked up Obama making a surprising request – probably not intended for journalists' ears – to outgoing Russian President Dmitry Medvedev, with whom he was having his last official meeting before Putin is inaugurated in early May.

Obama: On all these issues, but particularly missile defense, this, this can be solved but it’s important for (Putin) to give me space.

Medvedev: Yeah, I understand. I understand your message about space. Space for you…

Obama: This is my last election. After my election I have more flexibility.

Medvedev: I understand. I will transmit this information to Vladimir (Putin).

Russian experts say there's little doubt the Kremlin would like to see Obama re-elected. Official Moscow has been pleased by Obama's policy of "resetting" relations between Russia and the US, which resulted in the new START treaty and other cooperation breakthroughs after years of diplomatic chill while George W. Bush was president.

The Russian media often covers Obama's lineup of Republican presidential challengers in tones of horror, and there seems to be a consensus among Russian pundits that a Republican president would put a quick end to the Obama-era thaw in relations.

"The Republicans are active critics of Russia, and they are extremely negative toward Putin and his return to the presidency," says Dmitry Babich, a political columnist with the official RIA-Novosti news agency. "Democrats are perceived as more easygoing, more positive toward Russia and Putin."

Speaking on the record in Seoul, Mr. Medvedev said the years since Obama came to power "were the best three years in the past decade of Russia-US relations.… I hope this mode of relations will maintain between the Russian Federation and the United States and between the leaders."

But many Russian experts say that was mostly election rhetoric, and that in office Putin will seek greater cooperation and normal relations with the West.

"Russian society is more anti-American than its leaders are," says Pavel Zolotaryov, deputy director of the official Institute of USA-Canada Studies in Moscow. "Leaders have to take popular moods into account. But it's an objective fact that the US and Russia have more points in common than they have serious differences. If Obama wins the election, it seems likely the reset will continue."

No one seems sure whether Putin will be interested in aiding Obama's re-election at the expense of even a temporary suspension of Russian strategic concerns.

"Could we give Obama time? It's hard to tell what Putin thinks, but it seems to me we'd need to see some real sign there would be progress later, not just a few words," says Alexei Pushkov, chairman of the State Duma's foreign affairs committee. "If he's asking for time, what can he offer after that? If it's just some spoken promises, then probably not."

The Kremlin has repeatedly said that it would need ironclad written guarantees that the projected US-led missile defense shield would not be used to undermine Russia's Soviet-era nuclear missile deterrent, or else it would need to be allowed equal participation in a joint anti-missile system -– i.e., a Russian finger on the trigger – before it would drop its objections to US plans.

Mr. Pushkov says the Russians keep being told the planned shield is really aimed at Iran, not Russia. "But at the same time, they say they will soon force Iran to either drop its alleged nuclear weapon project, or use military means to curtail it. But missile defense deployments are planned to go ahead anyway. What will they tell us after they've dealt with Iran?"

Putin may also not be very keen to agree on Obama's proposed fresh round of nuclear arms cuts. That may be popular in the US, and around the world, but Russia, which relies on its mostly land-based force of intercontinental ballistic missiles for its national security, feels it's already cut enough.

"There's no way the next phase of the reset can be just another round of nuclear arms reductions," says Fyodor Lukyanov, editor of Russia in Global Affairs, a leading Moscow foreign policy journal. "There is a conceptual difference between Putin and Obama here. If Obama's idea is we should agree to new cuts first, and hold the worries about missile defense, then that's completely backwards from Moscow's point of view."